1. Field of the Invention
This invention relates to a liquid crystal display panel, and more particularly to a liquid crystal display panel wherein a lower substrate provided with a thin film transistor array has a constant distance from an upper substrate provided with color filters.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) panel consists of a lower transparent substrate, an upper transparent substrate and a liquid crystal injected into a space defined by an adhesion of the upper transparent substrate to the lower transparent substrate.
In the lower transparent substrate, a pixel array in which a plurality of thin film transistors each consists of a gate electrode, a gate insulating film, an active layer, an ohmic contact layer, source and drain electrodes is electrically connected to a pixel electrode to make each pixel. Also, a driving circuit is formed or installed on the lower transparent substrate. In the upper transparent substrate, color filters and black matrices used as light-shielding layers are formed.
In a fabricating process of the LCD panel, the lower substrate and the upper substrate are manufactured by a separate process. Then, the lower substrate and the upper substrate are adhered to each other by a sealant such that the pixel electrodes of the lower substrate are opposed to the color filters of the upper substrate at a desired distance to define a space. A liquid crystal is injected into this space.
FIG. 1 is a planar view showing a lower substrate of a conventional liquid crystal panel, and FIG. 2 is a sectional view showing a structure of a conventional LCD panel, which includes the lower substrate of FIG. 1, across line A-Axe2x80x2 of FIG. 1.
Referring to FIGS. 1 and 2, the conventional LCD panel consists of a lower substrate 10, an upper substrate 40 and a liquid crystal 45 filled in a space between the lower substrate 10 and the upper substrate 40.
The lower substrate 10 includes: a gate line 15; a data line 26; a thin film transistor positioned at a intersection of the gate line 15 with the data line 26; a pixel electrode 31 formed in a pixel area defined by crossing the gate and data lines 15 and 26; a spacer 43 on the intersection of the gate line 15 with the data line 26 for maintaining a constant distance between the upper and lower substrates The thin film transistor consisting of a gate electrode 13, a gate insulating film 17, an active layer 19, an ohmic contact layer 21 and source and drain electrodes 23 and 25 formed on a first transparent substrate 11. The gate electrode 13 is connected to a date line 15, and the source electrode 23 is connected to a data line 26.
A protective layer 27 covering the thin film transistors having the above-mentioned structure are formed on the gate insulating film 17, and a contact hole 29 exposing the drain electrode 25 is defined at this protective layer 27. On the protective layer 27 are provided a transparent pixel electrode 31 being in contact with and electrically connected to the drain electrode via the contact hole 29. Also, a first alignment film 33 covering a pixel electrode 31 is formed on the protective layer 27.
The upper substrate 40 has a black matrix 37 and color filters (not shown) formed on a second transparent substrate 35. The black matrix 37 is formed at a portion corresponding to the thin film transistor of the lower substrate, or a portion corresponding to the gate line 15 and the data line 26 including said portion corresponding to the thin film transistor. The color filters are formed in correspondence with the pixel electrode to filter and pass red(R), green(G) and blue(B) lights. A transparent common electrode 39 are formed at the front side of the second transparent substrate 35, and a second alignment film 41 is formed on this common electrode 39.
The lower substrate 10 and the upper substrate 40 are adhered to each other such that the thin film transistor is opposed to the black matrix 37. In this case, a spacer 43 for allowing the lower substrate 10 to have a constant distance from the upper substrate is provided. The spacer 43 is made from an organic insulating material. The spacer 43 is formed at an intersection between the gate line 15 and the data line 26 of the data line 26 of the lower substrate 10 to constantly keep a distance between the lower substrate 10 and the upper substrate 40. The spacer 43 may be formed at the lower substrate 10 or the upper substrate 40. A liquid crystal 45 is injected a space made by an adhesion of the lower substrate 10 to the upper substrate 40.
As described above, the conventional LCD panel has constantly keep a space between the lower substrate and the upper substrate adhered to each other by means of the spacer formed at an intersection between the gate line and the data line of the lower substrate or the upper substrate.
However, the conventional LCD panel has a problem in that, since the lower substrate requires a spacer for constantly keeping a space between the lower substrate adhered to the protective layer protecting the thin film transistor and the upper substrate and the upper substrate requires a black matrix for shutting off a light, its structure and its fabricating process become complex. Also, the conventional LCD panel has a problem in that, since it is necessary to define a contact hole for connecting the pixel electrode to the drain electrode, its fabricating process becomes complex
Accordingly, it is an object of the present invention to provide a liquid crystal display panel wherein a space between a lower substrate and an upper substrate can be constantly kept by means of a protective film pattern.
Another object of the present invention is to provide a liquid crystal display panel wherein an upper substrate thereof does not require a block matrix for shielding a light.
In order to achieve these and other objects of the invention, a liquid crystal display panel according to one aspect of the present invention includes: a first substrate and a second substrate spaced from and facing to each other to have a gap therebetween; a liquid crystal layer between the first and second substrate; a thin film transistor formed on the first substrate, the thin film transistor having a semiconductor pattern, a source electrode and drain electrode, a portion of the semiconductor pattern being exposed between the source electrode and the drain electrode; and a patterned spacer formed on the thin film transistor and supporting the second substrate, the patterned spacer having an insulating layer on the bottom which is in contact with the exposed portion or the semiconductor pattern.
The first substrate and the second substrate include a first alignment layer ants a second alignment layer respectively. A part of the first alignment layer contacts contact the second alignment layer on a top surface of the patterned spacer. The patterned pacer includes a nontransparent layer on the organic layer. The nontransparent layer is wider than the exposed portion of the semiconductor pattern.
The liquid crystal display panel further including a data line formed on the first substrate and electrically coupled to one of the source and drain electrodes. The organic layer of the patterned spacer extends over the data line.